package builder // This file contains the dispatchers for each command. Note that // `nullDispatch` is not actually a command, but support for commands we parse // but do nothing with. // // See evaluator.go for a higher level discussion of the whole evaluator // package. import ( "fmt" "io/ioutil" "path" "path/filepath" "regexp" "runtime" "sort" "strings" "github.com/Sirupsen/logrus" flag "github.com/docker/docker/pkg/mflag" "github.com/docker/docker/pkg/nat" "github.com/docker/docker/runconfig" ) const ( // NoBaseImageSpecifier is the symbol used by the FROM // command to specify that no base image is to be used. NoBaseImageSpecifier string = "scratch" ) // dispatch with no layer / parsing. This is effectively not a command. func nullDispatch(b *builder, args []string, attributes map[string]bool, original string) error { return nil } // ENV foo bar // // Sets the environment variable foo to bar, also makes interpolation // in the dockerfile available from the next statement on via ${foo}. // func env(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) == 0 { return fmt.Errorf("ENV requires at least one argument") } if len(args)%2 != 0 { // should never get here, but just in case return fmt.Errorf("Bad input to ENV, too many args") } if err := b.BuilderFlags.Parse(); err != nil { return err } // TODO/FIXME/NOT USED // Just here to show how to use the builder flags stuff within the // context of a builder command. Will remove once we actually add // a builder command to something! /* flBool1 := b.BuilderFlags.AddBool("bool1", false) flStr1 := b.BuilderFlags.AddString("str1", "HI") if err := b.BuilderFlags.Parse(); err != nil { return err } fmt.Printf("Bool1:%v\n", flBool1) fmt.Printf("Str1:%v\n", flStr1) */ commitStr := "ENV" for j := 0; j < len(args); j++ { // name ==> args[j] // value ==> args[j+1] newVar := args[j] + "=" + args[j+1] + "" commitStr += " " + newVar gotOne := false for i, envVar := range b.Config.Env { envParts := strings.SplitN(envVar, "=", 2) if envParts[0] == args[j] { b.Config.Env[i] = newVar gotOne = true break } } if !gotOne { b.Config.Env = append(b.Config.Env, newVar) } j++ } return b.commit("", b.Config.Cmd, commitStr) } // MAINTAINER some text // // Sets the maintainer metadata. func maintainer(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) != 1 { return fmt.Errorf("MAINTAINER requires exactly one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } b.maintainer = args[0] return b.commit("", b.Config.Cmd, fmt.Sprintf("MAINTAINER %s", b.maintainer)) } // LABEL some json data describing the image // // Sets the Label variable foo to bar, // func label(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) == 0 { return fmt.Errorf("LABEL requires at least one argument") } if len(args)%2 != 0 { // should never get here, but just in case return fmt.Errorf("Bad input to LABEL, too many args") } if err := b.BuilderFlags.Parse(); err != nil { return err } commitStr := "LABEL" if b.Config.Labels == nil { b.Config.Labels = map[string]string{} } for j := 0; j < len(args); j++ { // name ==> args[j] // value ==> args[j+1] newVar := args[j] + "=" + args[j+1] + "" commitStr += " " + newVar b.Config.Labels[args[j]] = args[j+1] j++ } return b.commit("", b.Config.Cmd, commitStr) } // ADD foo /path // // Add the file 'foo' to '/path'. Tarball and Remote URL (git, http) handling // exist here. If you do not wish to have this automatic handling, use COPY. // func add(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) < 2 { return fmt.Errorf("ADD requires at least two arguments") } if err := b.BuilderFlags.Parse(); err != nil { return err } return b.runContextCommand(args, true, true, "ADD") } // COPY foo /path // // Same as 'ADD' but without the tar and remote url handling. // func dispatchCopy(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) < 2 { return fmt.Errorf("COPY requires at least two arguments") } if err := b.BuilderFlags.Parse(); err != nil { return err } return b.runContextCommand(args, false, false, "COPY") } // FROM imagename // // This sets the image the dockerfile will build on top of. // func from(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) != 1 { return fmt.Errorf("FROM requires one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } name := args[0] if name == NoBaseImageSpecifier { b.image = "" b.noBaseImage = true return nil } image, err := b.Daemon.Repositories().LookupImage(name) if b.Pull { image, err = b.pullImage(name) if err != nil { return err } } if err != nil { if b.Daemon.Graph().IsNotExist(err, name) { image, err = b.pullImage(name) } // note that the top level err will still be !nil here if IsNotExist is // not the error. This approach just simplifies the logic a bit. if err != nil { return err } } return b.processImageFrom(image) } // ONBUILD RUN echo yo // // ONBUILD triggers run when the image is used in a FROM statement. // // ONBUILD handling has a lot of special-case functionality, the heading in // evaluator.go and comments around dispatch() in the same file explain the // special cases. search for 'OnBuild' in internals.go for additional special // cases. // func onbuild(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) == 0 { return fmt.Errorf("ONBUILD requires at least one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } triggerInstruction := strings.ToUpper(strings.TrimSpace(args[0])) switch triggerInstruction { case "ONBUILD": return fmt.Errorf("Chaining ONBUILD via `ONBUILD ONBUILD` isn't allowed") case "MAINTAINER", "FROM": return fmt.Errorf("%s isn't allowed as an ONBUILD trigger", triggerInstruction) } original = regexp.MustCompile(`(?i)^\s*ONBUILD\s*`).ReplaceAllString(original, "") b.Config.OnBuild = append(b.Config.OnBuild, original) return b.commit("", b.Config.Cmd, fmt.Sprintf("ONBUILD %s", original)) } // WORKDIR /tmp // // Set the working directory for future RUN/CMD/etc statements. // func workdir(b *builder, args []string, attributes map[string]bool, original string) error { if len(args) != 1 { return fmt.Errorf("WORKDIR requires exactly one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } // Note that workdir passed comes from the Dockerfile. Hence it is in // Linux format using forward-slashes, even on Windows. However, // b.Config.WorkingDir is in platform-specific notation (in other words // on Windows will use `\` workdir := args[0] isAbs := false if runtime.GOOS == "windows" { // Alternate processing for Windows here is necessary as we can't call // filepath.IsAbs(workDir) as that would verify Windows style paths, // along with drive-letters (eg c:\pathto\file.txt). We (arguably // correctly or not) check for both forward and back slashes as this // is what the 1.4.2 GoLang implementation of IsAbs() does in the // isSlash() function. isAbs = workdir[0] == '\\' || workdir[0] == '/' } else { isAbs = filepath.IsAbs(workdir) } if !isAbs { current := b.Config.WorkingDir if runtime.GOOS == "windows" { // Convert to Linux format before join current = strings.Replace(current, "\\", "/", -1) } // Must use path.Join so works correctly on Windows, not filepath workdir = path.Join("/", current, workdir) } // Convert to platform specific format if runtime.GOOS == "windows" { workdir = strings.Replace(workdir, "/", "\\", -1) } b.Config.WorkingDir = workdir return b.commit("", b.Config.Cmd, fmt.Sprintf("WORKDIR %v", workdir)) } // RUN some command yo // // run a command and commit the image. Args are automatically prepended with // 'sh -c' under linux or 'cmd /S /C' under Windows, in the event there is // only one argument. The difference in processing: // // RUN echo hi # sh -c echo hi (Linux) // RUN echo hi # cmd /S /C echo hi (Windows) // RUN [ "echo", "hi" ] # echo hi // func run(b *builder, args []string, attributes map[string]bool, original string) error { if b.image == "" && !b.noBaseImage { return fmt.Errorf("Please provide a source image with `from` prior to run") } if err := b.BuilderFlags.Parse(); err != nil { return err } args = handleJSONArgs(args, attributes) if !attributes["json"] { if runtime.GOOS != "windows" { args = append([]string{"/bin/sh", "-c"}, args...) } else { args = append([]string{"cmd", "/S /C"}, args...) } } runCmd := flag.NewFlagSet("run", flag.ContinueOnError) runCmd.SetOutput(ioutil.Discard) runCmd.Usage = nil config, _, _, err := runconfig.Parse(runCmd, append([]string{b.image}, args...)) if err != nil { return err } cmd := b.Config.Cmd // set Cmd manually, this is special case only for Dockerfiles b.Config.Cmd = config.Cmd runconfig.Merge(b.Config, config) defer func(cmd *runconfig.Command) { b.Config.Cmd = cmd }(cmd) logrus.Debugf("[BUILDER] Command to be executed: %v", b.Config.Cmd) hit, err := b.probeCache() if err != nil { return err } if hit { return nil } c, err := b.create() if err != nil { return err } // Ensure that we keep the container mounted until the commit // to avoid unmounting and then mounting directly again c.Mount() defer c.Unmount() err = b.run(c) if err != nil { return err } if err := b.commit(c.ID, cmd, "run"); err != nil { return err } return nil } // CMD foo // // Set the default command to run in the container (which may be empty). // Argument handling is the same as RUN. // func cmd(b *builder, args []string, attributes map[string]bool, original string) error { if err := b.BuilderFlags.Parse(); err != nil { return err } cmdSlice := handleJSONArgs(args, attributes) if !attributes["json"] { if runtime.GOOS != "windows" { cmdSlice = append([]string{"/bin/sh", "-c"}, cmdSlice...) } else { cmdSlice = append([]string{"cmd", "/S /C"}, cmdSlice...) } } b.Config.Cmd = runconfig.NewCommand(cmdSlice...) if err := b.commit("", b.Config.Cmd, fmt.Sprintf("CMD %q", cmdSlice)); err != nil { return err } if len(args) != 0 { b.cmdSet = true } return nil } // ENTRYPOINT /usr/sbin/nginx // // Set the entrypoint (which defaults to sh -c on linux, or cmd /S /C on Windows) to // /usr/sbin/nginx. Will accept the CMD as the arguments to /usr/sbin/nginx. // // Handles command processing similar to CMD and RUN, only b.Config.Entrypoint // is initialized at NewBuilder time instead of through argument parsing. // func entrypoint(b *builder, args []string, attributes map[string]bool, original string) error { if err := b.BuilderFlags.Parse(); err != nil { return err } parsed := handleJSONArgs(args, attributes) switch { case attributes["json"]: // ENTRYPOINT ["echo", "hi"] b.Config.Entrypoint = runconfig.NewEntrypoint(parsed...) case len(parsed) == 0: // ENTRYPOINT [] b.Config.Entrypoint = nil default: // ENTRYPOINT echo hi if runtime.GOOS != "windows" { b.Config.Entrypoint = runconfig.NewEntrypoint("/bin/sh", "-c", parsed[0]) } else { b.Config.Entrypoint = runconfig.NewEntrypoint("cmd", "/S /C", parsed[0]) } } // when setting the entrypoint if a CMD was not explicitly set then // set the command to nil if !b.cmdSet { b.Config.Cmd = nil } if err := b.commit("", b.Config.Cmd, fmt.Sprintf("ENTRYPOINT %q", b.Config.Entrypoint)); err != nil { return err } return nil } // EXPOSE 6667/tcp 7000/tcp // // Expose ports for links and port mappings. This all ends up in // b.Config.ExposedPorts for runconfig. // func expose(b *builder, args []string, attributes map[string]bool, original string) error { portsTab := args if len(args) == 0 { return fmt.Errorf("EXPOSE requires at least one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } if b.Config.ExposedPorts == nil { b.Config.ExposedPorts = make(nat.PortSet) } ports, _, err := nat.ParsePortSpecs(portsTab) if err != nil { return err } // instead of using ports directly, we build a list of ports and sort it so // the order is consistent. This prevents cache burst where map ordering // changes between builds portList := make([]string, len(ports)) var i int for port := range ports { if _, exists := b.Config.ExposedPorts[port]; !exists { b.Config.ExposedPorts[port] = struct{}{} } portList[i] = string(port) i++ } sort.Strings(portList) return b.commit("", b.Config.Cmd, fmt.Sprintf("EXPOSE %s", strings.Join(portList, " "))) } // USER foo // // Set the user to 'foo' for future commands and when running the // ENTRYPOINT/CMD at container run time. // func user(b *builder, args []string, attributes map[string]bool, original string) error { if runtime.GOOS == "windows" { return fmt.Errorf("USER is not supported on Windows") } if len(args) != 1 { return fmt.Errorf("USER requires exactly one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } b.Config.User = args[0] return b.commit("", b.Config.Cmd, fmt.Sprintf("USER %v", args)) } // VOLUME /foo // // Expose the volume /foo for use. Will also accept the JSON array form. // func volume(b *builder, args []string, attributes map[string]bool, original string) error { if runtime.GOOS == "windows" { return fmt.Errorf("VOLUME is not supported on Windows") } if len(args) == 0 { return fmt.Errorf("VOLUME requires at least one argument") } if err := b.BuilderFlags.Parse(); err != nil { return err } if b.Config.Volumes == nil { b.Config.Volumes = map[string]struct{}{} } for _, v := range args { v = strings.TrimSpace(v) if v == "" { return fmt.Errorf("Volume specified can not be an empty string") } b.Config.Volumes[v] = struct{}{} } if err := b.commit("", b.Config.Cmd, fmt.Sprintf("VOLUME %v", args)); err != nil { return err } return nil }